Barbaro, the Kentucky Derby Presented by Yum! Brands (gr. I) winner who had been making steady progress on his road to recovery from an injured right hind leg and a bout of laminitis, suffered a "significant setback" Tuesday night at the University of Pennsylvania's New Bolton Center.

In a released statement from the New Bolton Center Jan. 11, Barbaro's management has been changed to include sling support for several hours during the day, according to Dr. Dean W. Richardson, chief of surgery.

"He is getting up and down on his own and continues to eat and have stable vital signs. Radiographs (X-rays) taken yesterday (Jan. 10) revealed no additional complications in either hind leg. We are considering several additional therapeutic options at this time. He is stable and acceptably comfortable."

According to a statement from New Bolton released Jan. 10, Barbaro "became acutely more uncomfortable on his left hind foot. The foot cast was removed and some new separation of the medial (inside) portion of his hoof was found. This required some additional debridement (removal of the damaged tissue) last night."

Co-owner Gretchen Jackson said that the colt was lightly sedated and put back in a protective sling in his ICU stall.

"They're taking extreme measures," Jackson said. "They're treating it very aggressively. They're really pulling out all the stops to help him.

"Things were marching along pretty smoothly until this," Jackson said. "We've been there before with him. He's a horse that wants to live."

The setback comes one week after a new cast was put in place on the left hind foot, in which the Dynaformer colt had suffered a severe case of laminitis while being treated for the injury to his right rear leg. Barbaro has been at New Bolton since becoming injured in the May 20 Preakness Stakes (gr. I) and the new cast was designed to stabilize the foot as plans were being made for the colt to be relocated soon.

The cast change could have caused some inflammation, said Dr. Kathleen Anderson, Barbaro's attending vet when the horse was racing and stabled in trainer Michael Matz's barn at the Fair Hill Training Center in Elkton, Md.

Anderson said Barbaro has proved he was strong enough to overcome his latest medical obstacle.

"We all know most horses don't get this far," she said. "The bottom line with Barbaro is the fractured leg is the one that would have been the end of most horses. He won't be getting to the big green field any time soon, but I don't think this is insurmountable."

It was the first dose of bad news after months of progress that included owners Gretchen and Roy Jackson and Richardson talking about releasing Barbaro from the hospital as soon as the end of the month.

"It's sad that's he's had a setback because he was marching along toward living outside the hospital," Jackson said. "The only thing we care about is that he's not in pain."

Barbaro shattered his right hind leg in the Preakness. In mid-July severe laminitis, a potentially fatal disease caused by uneven weight distribution in the limbs, resulted in 80 percent of Barbaro's left hind hoof being removed.

"I was there yesterday and it was obvious he was not comfortable in that foot," Jackson said. "The easiest and best way to work on Barbaro is when he's laying down. They had to wait until he was laying down and when they removed the cast, they discovered some reason for him feeling pain."

Just over a week ago, Richardson said Barbaro's right hind was getting stronger and should eventually be healthy enough to allow the colt to live a comfortable, happy life.

But he also warned: "Barbaro's left hind foot, which had laminitis, remains a more formidable long-term challenge. The foot must grow much more for him to have a truly successful outcome."